export default{
  namespaced: true,
  
  state: ()=> ({
    //购物车的数组，用来存储购物车中每个商品的信息对象
    //每个商品的信息对象，都包含如下6个属性
    //{goods_id,goods_name,goods_price,goods_count,goods_small_logo,goods_state}
    cart: JSON.parse(uni.getStorageSync('cart') || '[]')
  }),
  
  mutations: {
    addToCart(state,goods){
      //根据提交的商品的id,查询购物车中是否存在这件商品
      //如果不存在，则findResult为undefined;否则，为查找到的商品信息对象
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      
      if(!findResult){
        //如果购物车中没有这件商品，则直接push
        state.cart.push(goods)
      }else{
        //如果购物车中有这件商品，则只更新数量即可
        findResult.goods_count++
      }
      //通过commit方法，调用m_cart命名空间的saveToStorage方法
      this.commit('m_cart/saveToStorage')
      
    },
    
    saveToStorage(state){
        uni.setStorageSync('cart',JSON.stringify(state.cart))
    },
    
    //更新购物车中商品的勾选状态
    updateGoodsState(state,goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      
      if(findResult){
        findResult.goods_state = goods.goods_state
        this.commit('m_cart/saveToStorage')
      }
    },
    
    //更新商品的数量
    updateGoodsCount(state,goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      if(findResult){
        findResult.goods_count = goods.goods_count
        this.commit('m_cart/saveToStorage')
      }
    },
    
    //根据id删除对应的商品
    removeGoodsById(state,goods_id){
      state.cart =  state.cart.filter(x => x.goods_id !== goods_id)
      this.commit('m_cart/saveToStorage')
    },
    
    
    //更新购物车中所有商品的勾选状态
    updateAllGoodsState(state,newState){
      state.cart.forEach(x => x.goods_state = newState)
      this.commit('m_cart/saveToStorage')
    }
    
    
    
    
    

  },

  getters: {
    //购物车中所有商品的总数量
    total(state){
      // let c = 0
      // state.cart.forEach(x => c += x.goods_count)
      // return c
     return state.cart.reduce((total,item) => total += item.goods_count,0)
    },
    //购物车中已勾选商品的总数量
    checkedCount(state){
      return  state.cart.filter(x => x.goods_state).reduce((total,item) =>  total += item.goods_count ,0)
    },
    
    //已勾选商品的总价格
    checkedGoodsAmount(state){
      return state.cart.filter(x => x.goods_state).reduce((total,item) => total += item.goods_count * item.goods_price,0).toFixed(2)
    }
    
    
    
  }
}